I want to use a RPi combined with a RC522 NFC reader to make a Mifare card-based authentication system(1). I am struggling with the capacity to read selected blocks of data on the NFC card.

I have been using information and code from PiMyLifeUp to read and write data on NFC cards. It works great.

I see however that this is limited to reading (not writing) the UID and reading and writing to block 8. I almost thought that I had the remaining of the information from a detailed answer but it stops short at what I did (and uses the same code).

My question: how to read and write any block?

(1) I initially intended to use an Arduino but even my limited initial tests show that the RPi is much more reliable in reading and writing the cards

1 Answer 1


I just realized that SimpleMFRC522.py defines the blocks to read and write:

BLOCK_ADDRS = [8, 9, 10]
  • Congratulations on answering - all on your own! One suggestion: You should click the "Accept" mark on your answer when you're able (may take a day or two??). That will signal others that this answer worked for you. Note that you can't upvote your answer (or your Q), but you can accept it.
    – Seamus
    Nov 6, 2023 at 16:46

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